STRUCTURE AND PROPERTIES OF BREAD DOUGH AND CRUMB - CALORIMETRIC, RHEOLOGICAL AND MECHANICAL INVESTIGATIONS ON THE EFFECTS PRODUCED BY HYDROCOLLOIDS, PENTOSANS AND SOLUBLE-PROTEINS

The effects of hydrocolloids (guar and locust bean gums), soluble pent osans, and whey proteins on staling of bread crumb were investigated b y means of DSC, rheometry, and image analysis. One current hypothesis, that these ingredients would behave as ''water binders'' and, at leas t the former two, as anti-staling agents, was indeed confirmed, althou gh this action might be indirect. All the samples considered showed an exothermic DSC peak preceding the endotherm of the amylopectin fusion . According to a previous work, this signal was attributed to a water- de pendent cross-linking process that would involve next-neighbouring polymer chains. To check the effect produced by molecular modification s that were expected to increase the water uptake of these ingredients , doughs containing added succinylated pentosans and whey proteins, an d a polycarboxylate polymer, PEMULEN TR-1, were examined. These modifi cations enhanced starch retrogradation and yielded a firmer crumb. It was tentatively concluded that some direct interaction between these m odified molecules and the crumb polymers might have taken place.In lin e with the food polymer science approach, the use of Time-Temperature- Transformation (TTT) diagrams is also discussed.